Is Antibacterial Soap Bad For You? (Part 2)

Last week, I introduced Triclosan, the most common active ingredient in antibacterial soaps, and explored some of the human health consequences of incorporating this compound into somanyconsumerproducts. From increasing antibiotic resistance to endocrine disruption, Triclosan has significant potential to cause human health problems. This week, we’ll look at some of the unexpected environmental effects that arise from rampant use of anti-bacterial soaps and personal care products: damaged ecosystems, drinking water contamination, and even an affected food supply. (The answer to the titular question is still yes, but now even more so!)

You know what would make this better? A butt-load of antibacterial soap.

Water, Water, Everywhere

Triclosan is one of the most common environmental contaminants in the developed world. And once it gets into lakes and streams, Triclosan can really mess up ecosystems by killing the plankton, cyanobacteria, and algae that form the foundation of aquatic food chains, and generally wreak havoc on ecologically-important microbial communities.

Yep, at concentrations as low as 0.52 micrograms per liter, Triclosan can interfere with the swimming ability of fathead minnows by inhibiting their ability to contract their muscles. As mentioned previously, Triclosan has been found to interfere with skeletal and cardiac muscle contraction in mice and human cell lines, too, so maybe it’s not a chemical that should be kicking around in the environment. Unfortunately, it’s kind of hard to get rid of quickly.

yeah, I caught this guy with nothing but patience and a bottle of Dawn

A Stubborn Contaminant

Wastewater treatment plants tend to be pretty good at getting Triclosan out of the water, or at least converting it into something else, but what it turns into and where it goes can be problematic. One of the breakdown products of Triclosan, 2,4-dichlorophenol, has been shown to be toxic to aquatic organisms and other breakdown products include dioxins. You may have heard of dioxins, because they are a group of some of the most persistent and toxic contaminants of the industrial age – well, a little sunlight and bad luck can convert Triclosan into one of those guys.

It’s not just any mud, it’s SPECIAL mud. It’s SCIENCE mud.

And it doesn’t just disappear, either. Regardless of what form it’s in, the Triclosan that is removed from the waste water has to go somewhere and it usually ends up in what is called “activated sludge.” Activated sludge is basically a type of mud that contains massive amounts of microbes which are responsible for turning our waste into compounds that are biologically useful. Around half of the Triclosan that goes down our collective drains ends up in the activated sludge where it can persist for hours to days. It can persist for even longer if the sludge is moved out of the plant and onto land somewhere.

Somewhere like, a farm, for example.

Remember when you didn’t have to worry about unknowningly eating antibacterial compounds? Good times. Good times.

Delicious, delicious Triclosan

In the United States, roughly 63% of the activated sludge used in waste water treatment plants is reused as fertilizer, meaning that Triclosan and its breakdown products may be coming into contact with human food crops. Even more alarming, recent studies have demonstrated that carrot, barley, and soybean crops are capable of absorbing Triclosan through their roots and distributing it to all parts of the plant – including the edible parts. Authors of the study on carrots and barley indicated that essentially all root vegetables are at particular risk for absorbing Triclosan and other undesirable contaminants.

I like to season my carrots with penicillin, too, because… Might as well?

There is hope, however, to avoid a Triclosan-infused future. A German research group found that environmental Triclosan levels dropped significantly following a general decrease in use of antibacterial soaps. This finding suggests that if we can kick our antibacterial obsession, if we can say no to advertisers and the allure of overpowered soap, we may live healthier Triclosan-free lives.

Great post! Wondering whether my UK carrots are anti-bacterial, too. Also wonder whether government regulations are in the making about this based on the scientific evidence, given the water issues we have already in the world. Probably not, given the turnover these products/germ panic generate…

Thanks, Angela! It’s hard to say how far along the legislation is on this. I know that the EPA is starting to look into Triclosan toxicity (http://www.epa.gov/oppsrrd1/REDs/factsheets/triclosan_fs.htm), but it’s going to be a while before they get that all sorted out. Maybe write to your representatives about the legislation? As you point out, it’s a tricky issue, given the general prejudices aimed at microbes, so it’s not likely to become a top policy priority any time soon.

Thanks for the comment, Robb! I’m not sure that anyone has actually looked for it in the food supply, but this study: http://dx.doi.org/10.1002/etc.1930 found that soybeans were able to pick up about 6-16% of the Triclosan in the soil, while radishes absorbed about 40%. This study: http://dx.doi.org/10.1021/jf301917q is the one I referenced about Triclosan absorption by carrots and barley. There isn’t a large body of literature on the topic of triclosan contamination in the food supply yet, but I expect that it will develop over the next few years as the compound receives renewed interest.

Why use anti bacterial products when your body has a perfectly good immune system to combat bacteria. People who use such products are only causing bacteria that are resistant to anti bacterial chemicals

Some very good points, Kumar! I would argue that there are judicious uses of antibacterial products in industrial and hospital settings where sterility is imperative. But, certainly, for the average consumer, there’s really no need for antibacterials.

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About Mind The Science Gap

Mind The Science Gap was a Science Communication Training blog that ran between 2012 - 2013.

Each semester, ten Master of Public Health students from the University of Michigan participated in a course on Communicating Science through Social Media. Each student on the course was required to post weekly articles here as they learned how to translate complex science into something a broad audience can understand and appreciate. And in doing so they were evaluated in the most brutal way possible - by the audience they were writing for!